This steel countersink drill bit set is used on steel, aluminum and other metals, plastic or wood. Enlarge or countersink holes, deburr edges. An ideal drill bit accessory for any fabrication shop with a manufacturer's lifetime warranty. Features: The four-piece set includes bits for drilling pilot holes for 3mm, 4mm, 5mm, 6mm screws. Specially designed steel countersink for pilot hole. Adjustable handle depth with a wrench. Drill and countersink for wood screws without changing bits. The drilling length can be adjusted for screws of different lengths simply by loosening and tightening the set screw. Chamfer is 5 flutes, in the process of use can discharge the wood faster, disposable sink hole drilled smooth, perfect screw cap embedded in the workpiece surface. Drill head: HSS 4241 with titanium coating. Heat treated and tempered high carbon steel with titanium coating for superior cutting power. Specifications: Material: HSS Drill 4241 Black Chamfer Drill Body: #45 Steel Chamfer Diameter: 15.8mm Size: 3mm x 60mm(L) / 4mm x 75mm(L) / 5mm x 85mm(L) / 6mm x 93mm(L) Shank: 1/4 Shank Package Size: 14 * 10 * 2cm / 5.51 * 3.93 * 0.78in Package Weight: 115g Note: Item color may show sight aberration due to different shooting light and monitor display. Package Included: 4pc * Woodworking Chamfer 1pc * Hex Shank